diff --git a/htdp-lib/info.rkt b/htdp-lib/info.rkt
index 3850a1dbd..3f92ade6b 100644
--- a/htdp-lib/info.rkt
+++ b/htdp-lib/info.rkt
@@ -21,7 +21,7 @@
     "slideshow-lib"
     "snip-lib"
     "srfi-lite-lib"
-    "string-constants-lib"
+    ["string-constants-lib" #:version "1.13"]
     "typed-racket-lib"
     "typed-racket-more"
     "web-server-lib"
diff --git a/htdp-lib/lang/htdp-langs-interface.rkt b/htdp-lib/lang/htdp-langs-interface.rkt
new file mode 100644
index 000000000..a93e95ad4
--- /dev/null
+++ b/htdp-lib/lang/htdp-langs-interface.rkt
@@ -0,0 +1,14 @@
+#lang racket/base
+(require racket/class)
+(provide htdp-language<%>)
+      
+(define htdp-language<%>
+  (interface ()
+    get-module
+    get-language-position
+    get-sharing-printing
+    get-abbreviate-cons-as-list
+    get-allow-sharing?
+    get-use-function-output-syntax?
+    get-accept-quasiquote?
+    get-read-accept-dot))
\ No newline at end of file
diff --git a/htdp-lib/lang/htdp-langs.rkt b/htdp-lib/lang/htdp-langs.rkt
index f2c023da8..10d583188 100644
--- a/htdp-lib/lang/htdp-langs.rkt
+++ b/htdp-lib/lang/htdp-langs.rkt
@@ -29,6 +29,7 @@
          lang/debugger-language-interface
          "run-teaching-program.rkt"
          "htdp-langs-save-file-prefix.rkt"
+         "htdp-langs-interface.rkt"
 
          (only-in test-engine/scheme-gui make-formatter)
          (only-in test-engine/racket-tests
@@ -59,17 +60,6 @@
       
       (define image-string "<image>")
       
-      (define htdp-language<%>
-        (interface ()
-          get-module
-          get-language-position
-          get-sharing-printing
-          get-abbreviate-cons-as-list
-          get-allow-sharing?
-          get-use-function-output-syntax?
-          get-accept-quasiquote?
-          get-read-accept-dot))
-      
       ;; module-based-language-extension :    (implements drscheme:language:module-based-language<%>) 
       ;;                                   -> (implements drscheme:language:module-based-language<%>)
       ;; changes the default settings and sets a few more paramters during `on-execute'
diff --git a/htdp-lib/test-engine/test-tool.scm b/htdp-lib/test-engine/test-tool.scm
index 5967e5dfb..641804049 100644
--- a/htdp-lib/test-engine/test-tool.scm
+++ b/htdp-lib/test-engine/test-tool.scm
@@ -1,7 +1,7 @@
 #lang scheme/base
 
 (require scheme/file scheme/class scheme/unit scheme/contract drscheme/tool framework mred
-         string-constants)
+         string-constants lang/htdp-langs-interface)
 (require "test-display.scm")
 (provide tool@)
 
@@ -149,13 +149,24 @@
                             (preferences:set 'test-engine:enable? #f)))
                         (super-instantiate ()))]
                      [enable? (preferences:get 'test-engine:enable?)]
-                     [enable-menu-item (make-object enable-menu-item%
-                                         (if enable? disable-label enable-label)
-                                         language-menu 
-                                         (lambda (_1 _2)
-                                           (if (send _1 is-test-enabled?)
-                                               (send _1 disable-tests)
-                                               (send _1 enable-tests))) #f)])
+                     [enable-menu-item
+                      (make-object enable-menu-item%
+                        (if enable? disable-label enable-label)
+                        language-menu
+                        (λ (menu-item _2)
+                          (cond
+                            [(is-a? (drscheme:language-configuration:language-settings-language
+                                     (send (get-definitions-text) get-next-settings))
+                                    htdp-language<%>)
+                             (if (send menu-item is-test-enabled?)
+                                 (send menu-item disable-tests)
+                                 (send menu-item enable-tests))]
+                            [else
+                             (message-box
+                              (string-constant drracket)
+                              (string-constant
+                               test-engine-enable-disable-tests-only-in-teaching-languages))]))
+                        #f)])
               
               (send enable-menu-item set-test-enabled?! enable?)
               (register-capability-menu-item 'tests:test-menu language-menu))))